February 16, 2011
By Staff Reporter
The low accumulation of mutations over time has made it one of the most useful tools available to geneticists, including Trinity College’s Dan Bradley, whose research team is interested in Ireland over the entire period humans have inhabited it.
The most high-profile research using the Y chromosome has been that which linked the male descendants of both Thomas Jefferson and his slave Sally Hemings and pointed to Jefferson or a close relative fathering one or more of her children. In all, about 30 percent of African-American males have European-type Y chromosomes
Proteges of Stanford University’s Luca Cavalli-Sforza, a pioneer in the field of genetics, have looked at the peopling of Europe over thousands of years using the Y chromosome. Academics have followed in more regional or national research projects. One such study has shown that the Finnish male population has a high incidence of a North Asian Y chromosome, while another points to a marked Viking influence in parts of Britain.
Modern genetic analysis has also given credibility to some popularly held beliefs. For instance, Jewish tradition, drawing on the Book of Exodus, says that the high priests, the kohanim, are all directly descended from Aaron, Moses’s brother. Research now indicates that about 50 percent of male Cohens (and other variants such as Kahn, Cohn, etc.) share a Y chromosome type, or a particular set of markers, indicating descent from one man. “That’s significantly higher than a random selection of people with the same type of Jewish ancestry,” Bradley said.
And similar methods, he added, have confirmed for the people of Iceland what they’ve always believed: that their ancestors came originally from both Scandinavia and Ireland/Scotland.